I think it's a waste of money. You're better off buying a generic multi-vitamin that only has 100% RDA for most vitamins/minerals-- it's cheaper and less risky. Airborne has too much Vitamin C (1670% RDA), which can cause kidney stones when taken in large doses. I've heard kidney stones can be extremely painful.
Here's an excerpt from wikipedia:
http://en.wikipedia.org/wiki/Airborne_(dietary_supplement)
There are some concerns. First, there is no conclusive evidence that this product or any of its ingredients prevents colds or shortens their duration. Second, the adult tablet contains 1 g of vitamin C, and the directions for use advise taking 1 tablet at the first sign of a cold and repeating the dose every 3 hours as necessary. Vitamin C in doses higher than 1 g increases oxalate and urate excretion and may cause kidney stones (EN Taylor et al, J Am Soc Nephrol 2004; 15:3225). Third, the safety of this herbal extraction combination has not been established. And with herbs and dietary supplements in general, we only have the manufacturers word on the label for whats in them.